more refactoring, rework FileCacheManager

MareSynchronos/Factories/FileCacheFactory.cs

@@ -1,4 +1,5 @@
 using System.IO;
+using System.Threading;
 using MareSynchronos.FileCacheDB;
 using MareSynchronos.Utils;
 
@@ -9,6 +10,11 @@ namespace MareSynchronos.Factories
         public FileCache Create(string file)
         {
             FileInfo fileInfo = new(file);
+            while (IsFileLocked(fileInfo))
+            {
+                Thread.Sleep(100);
+                Logger.Debug("File is locked, waiting for release: " + fileInfo.FullName);
+            }
             var sha1Hash = Crypto.GetFileHash(fileInfo.FullName);
             return new FileCache()
             {
@@ -24,5 +30,19 @@ namespace MareSynchronos.Factories
             cache.Hash = Crypto.GetFileHash(cache.Filepath);
             cache.LastModifiedDate = fileInfo.LastWriteTimeUtc.Ticks.ToString();
         }
+
+        private bool IsFileLocked(FileInfo file)
+        {
+            try
+            {
+                using var fs = file.Open(FileMode.Open, FileAccess.ReadWrite, FileShare.None);
+            }
+            catch
+            {
+                return true;
+            }
+
+            return false;
+        }
     }
 }